Asteroid Initiative Opportunities Forum ARRM Robotic Boulder Capture Option March 26, 2014 Dan Mazanek, LaRC Contributing NASA Centers & Academia: GSFC, ARC, GRC, JPL, KSC, MSFC, U. Colorado Boulder, U. Alaska Fairbanks 1 Abbreviations and Acronyms ACS Atude Control System LDRO Lunar Distant Retrograde Orbit ARCS Atude and Reac4on Control System MFOV Medium Field of View ARCM Asteroid Redirect Crewed Mission NEA Near-Earth Asteroid ARV Asteroid Redirect Vehicle NFOV Narrow Field of View BC Boulder Collecon NRE Non-Recurring Engineering CAD Computer Aided Design OpNav Op4cal Navigaon CCAR Colorado Center for Astrodynamics Research PHA Poten4ally Hazardous Asteroid CG Center of Gravity RCS Reac4on Control System DARPA Defense Advanced Research Projects Agency REU Robo4cs Electronics Unit DOF Degree(s) of Freedom S/C Spacecra EDU Engineering Development Unit SEP Solar Electric Propulsion EGT Enhance Gravity Tractor SLS Space Launch Vehicle EPS Electric Propulsion System TRN Terrain Relave Navigaon FH Falcon Heavy UAF University of Alaska - Fairbanks FOV Field of View WFOV Wide Field of View FOM Figure of Merit WP Way Point Front-end Robo4cs Enabling Near-term FREND Demonstraon GT Gravity Tractor HP Home Point IBD Ion Beam Deflec4on I&T Integraon and Test 2 Stakeholder Benefits Initial Human Mission Mars Forward Provides a well- Addresses and characterized, matures multiple accessible, multi-ton Mars-forward boulder for astronauts technology and to explore and return operations gaps, samples from, using a including operations mission approach that near and on the is robust to Martian moons, programmatic Phobos and Deimos. uncertainties. Returns a well- Science & Resources Planetary Defense characterized, Surface interaction provides access to with a hazardous-size potentially volatile/ NEA. Demonstrates water-rich one or more carbonaceous target deflection techniques and the opportunity for on a relevant target, hosted payloads – including the option to commercial, academic, test a kinetic impact and international approach. partners. Addresses the needs of a broad set of stakeholders, and leverages precursor missions and existing agency capabilities to ensure mission success. 3 Itokawa’s Boulder Rich Surface • Hayabusa mission confirmed the presence of many boulders on Itokawa’s surface. • Data from images suggest that several thousand 2 to 5 m boulders exist on Itokawa. • ~20% of the entire asteroid’s surface contains smooth areas (flat terrain with few hazards and wide access) – hundreds of boulder targets • Boulders are believed to be generated by impacts and appear to be common on NEAs. A – Hayabusa Touchdown Site 1 – Rocky Outcrop Areas 4,000,000 4 #on Est. Total 2 – Depressed Regolith with Boulders 3 & 4 – Infilled Impact Craters 400,000 40,000 4,000 3 400 Itokawa Ref: Noviello et al., 2014 40 2 > D* 4 1 * Added axis based on Itokawa surface area of 0.4011 km2 4 Hayabusa Touchdown Site Approach • Smooth areas have boulders sitting on a surface dominated by gravels and pebbles. Stereo image analysis indicates a high probability that some boulders5m are not embedded. • Highest resolution of the images during the Hayabusa touchdown are 6 to 8 mm/pixel. • Evidence from Hayabusa and ground-based radar suggests that boulders may be relatively common on near-Earth asteroids (e.g., Bennu and 2005 YU55). • This evidence is supported by theoretical and laboratory analysis of asteroid rubble pile formation and impact processes. (Solar angle ~10 degrees) 5 Boulder Characteristics • Low probability boulders will crack/crumble during collection • Boulders are most likely the result of a collision and reaccumulation process which means they have withstood forces much greater than the what will be seen during the collection process (< 350 N). • Friability of the boulder is dependent on the type of asteroid, but is expected to be sufficiently low to facilitate collection operations. • High resolution imagery will be obtained prior to collection to provide detailed shape model and identify any defects to ensure successful collection. Material Typical Compressive Strength Ordinary chondrite 6.2 - 420 MPa 900 - 61,000 psi Concrete 20 MPa 3000 psi Carbonaceous 0.3 - 50 MPa 44 - 7,250 psi Charcoal Briquee ~3 MPa 440 psi • Mass properties will be highly characterized with low uncertainty • Boulders are likely homogenous with a near constant density. Shape of boulder will be known (< 1 cm resolution) and mass properties estimates will be well within vehicle performance. • Visual inspection of boulders will provide a reasonable estimate of density compared to the parent body. Density of Itokawa material is known from Hayabusa, further reducing uncertainty in mass of boulders for that target. 6 Boulder Aspect Ratio • Spherical boulder sizes in this presentation assume represent the smallest maximum extent for a given mass and density. For example: − A 10 t carbonaceous boulder with density of 1.62 g/cm3 has a 2.3 m spherical extent. − This mass and density would have a maximum extent of ~3.3 m for 3:3:1 aspect ratio. Spherical boulders represent the minimum possible size extent for a given mass and density. Aspect RaZo Mass Volume Maximum Extent (t) (m3) (m) 1:1:1 10 6.14 2.3 2:2:1 10 6.14 2.9 3:3:1 10 6.14 3.3 1m Assumes carbonaceous material with density = 1.62 g/cm3 7 Itokawa: Case Study Why Itokawa? • Meets valid candidate criteria. • Leverages Hayabusa as a precursor mission to reduce mission costs and programmatic/technical risks. • Hayabusa instrumentation has provided a high confidence in ability to find many selectable boulder targets. Launch on 0.8 t ,0.8 m 5 t ,1.4 m 18 t ,2.2 m 20 t ,2.3 m Falcon Heavy after June 2019 1m LDRO Crew 10.5 t ,1.8 m 19 t ,2.3 m Availability: 2024 2025 2026 2027 Size assumes spherical shape Developed a detailed mission to Itokawa to: • Assess options and risks associated with proximity operations. • Understand spacecraft design requirements differences. • Develop sufficient fidelity to inform cost & schedule estimates. Ability to increase mission success and robustness by targeting well- characterized asteroids and to accommodate uncertain programmatic schedules by tailoring the return mass. 8 Target Availability and Boulder Size and Mass • One Valid Candidate with hundreds of candidate boulders: Itokawa • Two candidates may be characterized by precursors in 2018: Bennu (OSIRIS-REx) & 1999 JU3 (Hayabusa 2) * • One candidate characterized by radar at ~6000 SNR: 2008 EV5 • At least two more candidates may be sufficiently characterized by radar during the next 4 years: 2011 UW158, 2009 DL46 ~3.22 g/cm3 ~1.62 g/cm3 ~1.62 g/cm3 ~1.62 g/cm3 Spherical maximum returnable boulder size ranges from 1.5 m to 4 m enabling a large range of boulder size for retrieval. * Personal communication Michael Bush (ref. Busch et al., Icarus Volume 212, Issue 2, April 2011, Pages 649–660) 9 Returnable Boulder Size Trends Itokawa Best Performance for FH Missions with duration >5 years can launch any year and return a ~2+ meter boulder from Itokawa or Bennu providing mission robustness to schedule changes. Itokawa Synodic Period ~2.9 yrs Similar performance expected for: Bennu Best Performance for FH 1999 JU3 synodic period ~4.3 2008 EV5 synodic period ~15.7 Bennu Synodic Period ~6 yrs 10 Mission Profile Comparison – Candidate Targets Itokawa Itokawa 1999 JU3 Bennu 2008 EV5 Phase/AcZvity Mid 2025 Late 2025 2025 2024 2024 Date/Dur Xenon Use Date/Dur Xenon Use Date/Dur Xenon Use Date/Dur Xenon Use Date/Dur Xenon Use June 20, June Sept. 6, June 1, July 28, Launch 2019 17,2019 2019 2019 2019 Outbound Leg 2.2 years 4,020 kg 2.2 years 4,080 kg 1.6 years 2,400 kg 2 years 3,740 kg 2 years 3,120 kg Asteroid Rendez & Prox Ops Sept. 11, Aug. 17, March 24, June 6, June 3, Arrival 2021 2021 2021 2021 2021 Characterizaon & 51 days 55 days 51 days 55 days 55 days Capture Capture Phase Margin 18 days 51 days 18 days 51 days 51 days Planetary Defense 262 days 170 kg 262 days 170 kg 273 days TBD kg 285 days TBD kg TBD days TBD kg Demo Proximity Operaons 69 days 30 kg 69 days 30 kg 69 days 30 kg 69 days 30 kg 69 days 30 kg Margin Oct. 16, Sept. 21, May 28, July 11, July 8, 2022 Departure 2022 2022 2022 2022 Inbound Leg 2.5 years 1830 kg 2.8 years 1,750 kg 2.7 years 4,720 kg 1.5 years 3240 kg 1.5 years 3,960 kg Earth-Moon System DRO August, November, 70 kg (TBR) 70 kg (TBR) May , 2025 70 kg (TBR) May, 2023 70 kg (TBR) May, 2023 70 kg (TBR) Inser4on 2025 2025 Aug-Sept. Nov. -Dec. May-June May-June May-June Earliest ARCM Availability 2025 2025 2025 2024 2024 Xe used: 6,230 kg Xe used: 6,200 kg Xe used: 7,500 kg Xe used: 7,360 kg Xe used: 7,500 kg SEP Operating Time: TBD days SEP Operating Time: TBD days SEP Operating Time: TBD days SEP Operating Time: TBD days SEP Operating Time: TBD days Assumes Heavy Lift Launch Boulder Return Mass: 11 t Boulder Return Mass: 18 t Boulder Return Mass: 10 t Boulder Return Mass: 6 t Boulder Return Mass: 13 t Vehicle (Falcon Heavy) (1.8 m spherical, 2.3 m max (2.2 m spherical, 2.8 m max (2.5 m spherical, 3.1 m max (1.9 m spherical, 2.4 m max (2.5 m spherical, 3.1 m max extent @ 2:2:1 Aspect Ratio) extent @ 2:2:1 Aspect Ratio) extent @ 2:2:1 Aspect Ratio) extent @ 2:2:1 Aspect Ratio) extent @ 2:2:1 Aspect Ratio) 11 Spaceframe Concept Spaceframe capture system employs simple, repetitive design with only 42 unique machined parts and no new technology.